The first automated analyzers utilizing ion selective electrodes for measuring electrolytes in whole blood, plasma, or serum were developed in 1975 by Orion Research Incorporated. Orion's model SS-30 measured potassium and sodium, and its model SS-20 measured ionized calcium. Since that time, other analysers have been developed by Corning, Model 902; Instrumentation Laboratory, Models 501, 502, and 504, which are described in U.S. Pat. No. 4,283,262 granted Aug. 11, 1981, to Cormier et al. and U.S. Pat. No. 4,304,257, granted Dec. 8, 1981, to Webster; Nova Biomedical Corporation, Nova 1, 4, and 5; Kone OY, Microlyte; Radiometer, Model KNAI; Guilford Chemlyte NA/K; Beckman, Electrolyte 2 and System E4A; AVL Model 980; Dow Corning Direction 6000; Worthington, IE8200; and Photovolt 4M.
A most recent and advanced unit in the art is Orion's Model 1020. It does, however, have some limitations. First, it has separate bottles for its standardizing and maintenance solutions as well as a bottle to collect spent reagents and sample solutions. The operator is required to place different tubes in each bottle, and to change the bottles at different times. Orion's earlier model SS-30 utilized a cardboard fluids pack containing individual laminate reagent pouches and a plastic disposal bag into which separate plastic tubes were placed. Secondly, the Model 1020 requires manual operator interactive calibration procedures to adjust pumping to compensate for physical change in the peristaltic pump tubing. A third limitation is an expensive carriage assembly containing the ion selective electrodes, reservoir housing, and sample probe, all which have to be moved up and down when the analyzer aspirates a sample. The present invention overcomes these limitations.
The principal object of the invention is to provide a mechanically simple, low cost, user friendly, fully automated, electrolyte analyzer.
Another object is to provide an electrolyte analyzer with continuous and automatic pump tubing calibration.
Another object of the invention is to provide a stat electrolyte analyzer with a unique and automatic detection system for sensing bubbles or air segments, and for determining sample and reagent position.
Yet another object is to provide an electrolyte analyzer having an integrated reagent and waste disposal system.